On Jan 22, 9:21 am, sie...@[EMAIL PROTECTED]
wrote:
> Would a small solid object (such as a bullet
> or a billiard ball) moving at 99.999% of c tend to simply punch
> through other solid objects (such as a human or a brick wall) because
> there is no time for chemical bonds to spread the impact energy? Or
> would it liberate a significant amount of its KE on impact? Would
> impact result in forcing some nuclei so close together that fission
> and/or fusion reactions are likely? Would this be the ultimate needle
> gun, or the ultimate "explodes on contact" effect? What if the object
> struck is more sizable, such as an asteroid or planet.
The energies per particle are well above the energies of the chemical
bonds holding the object together (and those holding the "target"
object together). As soon as "contact" occurs between the two
objects, the electrostatic electron-electron and electron-nuclei
forces will jostle the electrons enough that they are excited out of
chemical bonding states and into high energy so-called conduction
states, turning the impactor into a very hot plasma, and as well as
whatever part of the target the impactor is traveling through. The
particles in the impactor still have so much momentum and energy that
they continue to punch through the target, even though they are now a
spray of penetrating ionizing radiation rather than a solid object.
They will be slowed down somewhat as the highly charged particles
continue to lose energy by exciting electrons in the target, but this
effect will be minor for the nuclei at the speeds you mention.
Instead, the dominant method of stopping the nuclei of the impactor
will be direct collisions with nuclei of the target. This will result
in a spray of radiation from the debris and nuclear fragments, which
continue to heat up the target by producing electronic excitations
while also occasionally slamming into another nucleus, causing further
fragmentation. This cascade of radiation producing collisions
continues until the speed of the nuclear fragments slows down enough
that electronic losses are the dominant energy loss mechanism, at
which point the nuclear fragments dump the rest of their energy into
the electrons and come to a stop. Meanwhile, the gamma rays and muons
produced by these collisions will penetrate deeply and, depending on
the target's thickness, may largely exit the target altogether, and
the neutrinos produced will escape the target altogether.
At high energies like you specified, a nucleus or nuclear fragment
(including pions and kaons) will travel roughly a meter before
slamming into another target nucleus. As a result, you will get a
narrow cone of radiation extending several meters to several tens of
meters into the target. The heat dumped into the target raises the
temperature in that narrow cone to well above the temperatures in the
center of a detonating nuclear explosive or the core of a sun, with
the temperature being hottest near the end of the cone. The matter in
the cone immediately begins shedding heat via the radiation of x-rays,
which heats the surrounding matter until it, too, begins to radiate.
This diffusion of heat by radiation is at first much faster than the
matter itself can move, so you get a radiative front expanding from
the cone, va****izing everything it passes through. Eventually, the
fireball thus produced cools sufficiently that the transfer of heat
via radiation is slowed, and the super-heated matter has time to
expand. The expanding fireball produces a shock wave. The net result
is somewhat similar to a nuclear blast, with a pulse of scorching heat
and blazing light from the incandescent fireball and a shock that
smashes buildings and blows people and debris about. If the entire
energy of the impactor is absorbed in the target, you will get a yield
of roughly 5,000 megatons per kilogram of impactor at the speed of
99.999% c that you mentioned. Even an impact with a thin object (say
a human) that does not fully stop the impactor will have a yield
comparable to or in excess of that of a large nuclear explosive.
Luke
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